Renowned as great centres of learning, the cities of Baghdad and Isfahan were at the heart of the Islamic civilization as rich capital cities and centres of intellectual thought. Their distinct cultural voices inspired a unique historical dialogue, which finds new expression in Baghdad and Isfahan, the story of how knowledge was transmitted and transformed within Islamic lands, and then spread across Europe. Capturing the history of Baghdad and Isfahan from 750 to 1750, Elaheh Kheirandish draws on the voices of court astronomers, mathematicians, scientists, mystics, jurists, statesmen and Arabic and Persian translators and scholars to document the extensive and lasting contribution of sciences from Islamic lands to the history of science. Kheirandish bases her narrative on a unique medieval manuscript and other historical sources and the result is more than a thousand-year 'tale of two cities' - it is a city by city, and century by century, look at what it took to change the world. In a feat of travelogue and time travel, this unique book creates parallel stories with modern and historical characters, crossing cities worldwide, and capturing changes through time. Interweaving multiple narratives, histories, and futures, she charts the possible paths - formalized and serendipitous, lost and recovered - by which knowledge itself is translated and transmitted across time and cultures.